And so the usual winter conditions here meant the car had to work harder and burn more fuel to operate "normally". Mileage wasn't horrifying when I was in Augusta (low 20s if I recall), but it wasn't reaching the levels Sideways mentioned. I'd kill for 30mpg.

None of which is relevant for a touge MR2 because that sort of power would be a total waste. 400 HP is pretty much the limit... and an SW20 is already way too heavy with the 3S in the back, never mind a twin turbo V6.

The twin turbo V6 was just an example of the potential of the 1MZFE conversion with forced induction added.

However, a 2GRFE V6 is a good 20kg lighter then a 3SGTE and has proven to punch out a good 300+BHP in NA form with nothing more then a less restrictive exhaust. With some improvements like camshafts, intake design and some quality engine management, 350-400HP should be achieveable and could indeed make a good fan fiction based car.

Cold air into the engine actually makes it more efficient because it doesn't have to work as hard. The air is denser, taking in the same amount of air yields more oxygen, so you don't need to be on the gas as much. But the combining factors of cold on other parts of the car, like thicker fluids, a less efficient gas that stations carry in winter, less pressure in the tires from colder air, the affect of thicker air on drag, or the engine itself taking longer to heat up, combine to drag your MPG down, and lead to an urban myth that colder intake air makes worse mileage.

Cold air into the engine actually makes it more efficient because it doesn't have to work as hard. The air is denser, taking in the same amount of air yields more oxygen, so you don't need to be on the gas as much.

Das is true, ja, but since thicker air means the ECU or carbs add more fuel (which is less efficiently burned because of lower temperatures), and people usually don't drive differently to compensate for an increase in power, you're probably going to end up burning more fuel for the same distance.

That said, you will have much more power when it's cold, especially with a turbo engine.

FWIW, dyno numbers compensate for ambient temperature by calculating the power at a given temperature, a given barometric pressure, and a given humidity (77 degrees F and 0% humidity at approximately seal level pressure for SAE horsepower). Just an interesting fact...

My car starts without the need for a choke when it's above 70F outside. Which I only know because my dad broke the electric choke so I removed it completely. Hard as hell to start the car when it's cold but when it's hot out no problem!

Typically speaking an engine is going to be more "efficient" (to an extent) in colder weather than in hotter weather, and make more power. We can observe this easily on a dyno where engines typically produce higher numbers in cooler weather (again, to an extent).

And like banken already pointed out- Colder air is denser. Denser air means youre motor will ingest more oxygen per revolution. And most cars compensate for this extra oxygen by adding more fuel to maintain a desired afr. (Side note: This is assuming an efi set up. In all honesty im pretty ignant on what would happen in the same instance if you had a carb. As carbs work off of air velocity causing a vacuum to pull fuel into the intake as they pass a channel in the itnake plenum that connects to a fuel bowl. While i wouldnt be surprised if it makes some difference, im not sure if air density will make as much of a difference to a carb as it would to an efi car. Anyone know if their carbed cars see a difference in AFRs during winter/summer seasons?)

Other factors come into play as well. Again back to colder/denser air- Your car has to push through more air to cruise. The difference is slight, but there is an increased drag on the car as the weather cools down. Its also worth pointing out that this colder weather will reduce pressure in your tires as the air inside them cools/contracts causing a larger footprint and more rolling resistance. Of course this is readily correctable, but in realist almost no one does.

Not adding much to whats been stated- just confirming a few things.

Colder weather, your car does make more power. You also get a decrease in gas mileage. Before I made the move to aussie land i frequently made 300 mile trips back and forth between vegas and la (visiting friends and family at both sides). Quite often this was literally -every- weekened for months on end. Even in the "slower" times I never went more than a couple of weeks without a trip. I did this for years. My wallet readily looked forward to warmer times. My corolla after the 20v swap would go from mid 30s to low 30s average like clockwork as the weather changed.

Are you kidding me? You have to re-tune a carb for altitude. You tell me if air density matters to a carb.

Haha imma blame 4 hours of sleep and it being 2 am for the vagueness on that one. I know theyd have to be retuned for different air densities, im just unsure of how much itll effect how much fuel is actually going into the engine when the density changes.

When I had suspect tires, worn suspension bushes and a right foot that wasn't used to 240hp ish I managed to end up facing the wrong way down a dual carriage after giving it to much gas on the exit from a roundabout.

Fortunately there were no cars around me and I was able to avoid the barriers by mainly luck.

Two months later with decent rubber, and renewed suspension the grip seemed unbreakable providing you transitioned to acceleration smoothly, however in the wet the 'fear' was always there!

Incidentally, I found it to be excellent in the snow, with the engine over the tires, traction was pretty good, and unlike a FWD the front end didn't wash out so much because you give it some gas to pivot the car to the inside.

In heavy snow the front end will wash out and the back end won't stop once it comes out. But as long as you're careful it's fun. But the real issue is that being so low, once it gets stuck, it's stuck. Unless you have an aftermarket LSD. The stock viscous is worthless in snow because one wheel will just spin while the other won't move.It also helps to put weight in the front.

I'm still not sure whether it handles better on the track with the spare tire in or out.

Also, tires make more of a difference than anything else, even if your suspension is bad.

With dry-rotted sporty tires (first time I drove the car, which happened to be on the track) I couldn't even dream of using the gas in turns, but it was no problem with new sports tires.

Or just do what I did and go with the Gen4 3SGTE. They can be had for just over $1k. You can re-use the S54 transmission with a custom friction disc and it's bolt in. Wiring harness conversion to plug and play is like $400. I probably spent about $2500 for everything (complete re-seal, water pump t-stat and waterpump, cv axle rebuilds and other maintenance). In stock form it's at least at 250hp with added upgraded IC, intake, downpipe and 3" exhaust I can't imagine I'm far from 300hp at stock boost. Oh, it retains stock AC and Cruise to boot. I've also logged 28mpg combined fuel economy. Can't beat that considering the power output.

Well I'm back in an MR2 again now, so its definitely a car I liked! Rev 3 + is 240hp standard compared to the Rev 2 which is 220.

Upgraded IC and manifold + exhaust are all sensible mods and should have netted you a few HP. I personally use the standard airbox, from my research its better than aftermarket induction kits and plenty of people make big power with it.

I very much doubt you'll make close to 300 without an increase in boost, maybe 255-260 ish. You'd maybe get 300ish at 16-28psi.